Aircraft are symmetric in plan view.  Lift is balanced around the fuselage.  Sailrocket has symmetry in force balance, the single element wing and Bruce foil balance in opposition.  So low drag makes sense in these cases.  Tacking and shunting sail boats are not symmetric in this opposing or balanced forces sense.  Lift is counterbalanced by mass to windward on multis and monos alike (and more recently with DSS foils to leeward).  Mass righting moment is a constant allowing for mass shifting to windward (or with increased drag penalty with water ballast).  Mass has a hydro drag penalty on narrow platforms (i.e. keels) and a parasitic aero drag penalty on wider platforms.  Absolute righting moment cannot be scaled with healing moment.  So sailing craft carry lots of excess drag baggage already and must depower once lift exceeds righting moment.  The goal is to generate lots of lift as low as possible which is why the AC72's have tapered bottom endplated 2 element rigs.  Your single element will be taller than the equivalent wingmast and sail, or two element wing (4 times the lift) so you must depower before you generate as much lift.  Or the single element must be more squat and consequently draggy anyway.  The AC72's can even reverse the lift at the top of the rig through twist, generating additional righting moment.

Blakeley 2 element shows a Cl of 3.5 with a Cd 0.3.  The thick single element, Cl of 0.9 Cd of 0.08.  Similar ratios.

Talador: If you want to sail slowly use flaps : )

The smiley excuses this?  Rather than smileys and back of the envelopes I suggest you set about crowd funding the next America's Cup challenge with a single element wing.